Engineered stretch knit upper improves breathability: External back heel counter helps keep the foot stable and provide a more comfortable stride: 4D GUIDANCE SYSTEM feature: Helps create adaptive stability for a more balanced stride Rearfoot PureGEL technology: Helps provide lightweight cushioning and softer landings FF BLAST PLUS ECO cushioning is made with approximatley 20% bio-based content and helps provide cloud-like comfort: Colour: blue